Seventh chord

Most textbooks name these chords formally by the type of triad and type of seventh; hence, a chord consisting of a major triad and a minor seventh above the root is referred to as a major/minor seventh chord. When the triad type and seventh type are identical (i.e. they are both major, minor, or diminished), the name is shortened. For instance, a major/major seventh is generally referred to as a major seventh. This rule is not valid for augmented chords: since the augmented/augmented chord is not commonly used, the abbreviation augmented is used for augmented/minor, rather than augmented/augmented. Additionally, half-diminished stands for diminished/minor, and dominant stands for major/minor. When the type is not specified at all, the triad is assumed to be major, and the seventh is understood as a minor seventh (e.g. a "C" chord is a "C major triad", and a "C7" chord is a "C major/minor seventh chord", also known as a "C dominant seventh chord"). For symbols used for seventh chords, see also . Tertian The most common chords are tertian, constructed using a sequence of major thirds (spanning 4 semitones) and/or minor thirds (3 semitones). Since there are 3 third intervals in a seventh chord (4 notes) and each can be major or minor, there are 7 possible permutations (the 8th one, consisted of four major thirds, results in a non-seventh augmented chord, since a major third equally divides the octave). The five commonly found in western music are the major seventh, the minor (or minor/minor) seventh, the dominant (or major/minor) seventh, the half-diminished seventh, and the diminished seventh. The less commonly found tertians are the minor major seventh and the augmented major seventh. Non-tertian Seventh chords can also be constructed using augmented or diminished thirds. These chords are not tertian and can be used in non-tertian harmony. There are many (mathematically, 64) chords that can be built, however, only a few of them are used in Western music. In tuning systems other than equal temperament there are further possible seventh chords. In just intonation, for example, there is the harmonic seventh. == Types ==

Dominant seventh chord {{Image frame|content= { \override Score.TimeSignature #'stencil = ##f \relative c'' { \clef treble \time 4/4 1 } } |width=120|caption=The dominant seventh chord (V7) in C major, G7}} A dominant seventh chord, or major-minor seventh chord is a chord composed of a root, major third, perfect fifth -- a major triad -- with an additional minor seventh. It is denoted using popular music symbols by adding a superscript "7" after the letter designating the chord root. The dominant seventh is found almost as often as the dominant triad. Frequent use of the harmonic seventh chord is one of the defining characteristics of blues and barbershop harmony; barbershoppers refer to it as "the barbershop seventh". Since barbershop music tends to be sung in just intonation, the barbershop seventh chord may be accurately termed a harmonic seventh chord. The harmonic seventh chord is also widely used in blues-flavored music. As pianos, and other equal-temperament instruments cannot play this chord, it is frequently approximated by a dominant seventh. As a result, it is often called a dominant seventh chord and written with the same symbols (such as the blues progression I7–V7–IV7). Major and minor seventh chords {{Image frame|content= { \override Score.TimeSignature #'stencil = ##f \relative c' { \clef treble \time 4/4 1 } } |width=120|caption=The minor seventh chord (ii7) in C major, D–7}} While the dominant seventh chord is typically built on the fifth (or dominant) degree of a major scale, the minor seventh chord is built on the second, third, or sixth degree. A minor seventh chord contains the same notes as an added sixth chord. For example, C–E–G–B can function as both a C minor seventh and an E added sixth (Id chord).{{Image frame|content= { \override Score.TimeSignature #'stencil = ##f \relative c' { \clef treble \time 4/4 1 } } |width=120|align=right|caption=The major seventh chord (IV7) in C major, F7}} Major seventh chords are usually constructed on the first or fourth degree of a scale, (in C or G major: C–E–G–B). Due to the major seventh interval between the root and seventh (C–B, an inverted minor second), this chord can sometimes sound dissonant, depending on the voicing used. For example, Bacharach and David's "Raindrops Keep Fallin' on My Head" opens with a major chord followed by a major seventh in the next measure. The major seventh is sometimes notated as 7 (a delta chord) or just a (which has the same meaning). Half-diminished seventh chord {{Image frame|content= { \override Score.TimeSignature #'stencil = ##f \relative c' { \clef treble \time 4/4 1 } } |width=120|caption=The leading-tone seventh chord (vii7) in C major, B7}} A half-diminished seventh chord is a seventh chord built from the seventh degree of a major scale. It is considered "half-diminished" because a fully diminished seventh has a double-flatted (diminished) seventh, making it enharmonically the same as a major sixth. The half-diminished seventh chord uses a minor seventh over the root of a diminished triad. Example: (in the key of C major) B–D–F–A. Diminished seventh chord {{Image frame|content= { \override Score.TimeSignature #'stencil = ##f \relative c' { \clef treble \time 4/4 1 } } |width=120|caption=The diminished seventh chord on B}}A diminished seventh chord is made of three superimposed minor thirds (e.g., B–D–F–A), which is two tritones a minor third apart (e.g., B–F, D–A). The diminished seventh chord has been used by composers and musicians for a variety of reasons over time. Some reasons include: as a symbol of Sturm und Drang; modulation; and for characterisation. The diminished seventh chord is seen more frequently in late classical and romantic period works but is also found in Baroque and Renaissance period works, though not as frequently. All of the elements of the diminished seventh chord can be found in the dominant seventh flat nine (79) chord as seen in a comparison of the two chords. ==Inversions==

: { 1^\markup { \column { "Root" "position" } } 1^\markup { \column { "First" "inversion" } } 1^\markup { \column { "Second" "inversion" } } 1^\markup { \column { "Third" "inversion" } } } \figures { 1 } >> } There are four different inversions of a seventh chord. Following basso continuo notation, the inversions are as follows: • V: GBDF • V: BDFG • V: DFGB • V or : FGBD Additional numbers are used to indicate the seventh chords and their inversions. ==See also==